Device for connecting a drill column to a pipe or the like

ABSTRACT

An actuating system for operating pressure-medium actuated coupling members for remotely connecting a drill column to a pipe or pipe casing, where the location of the connection is inaccessible, comprises a directional control valve (48) switchable by an actuator (46) and having at least three connections (51, 52, 53), a coupling (47) operated in one direction by the actuator disposed between the actuator (46) and the adjustable part of the directional valve (48). The coupling members may be a plurality of radially movable bearing members (34) and bars (24) spaced apart in the axial direction of the device.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a device, i.e. a unit for incorporation in adrill column for releasably connecting the drill column to a pipe orsimilar hollow member, comprising coupling members for attaching to thepipe and associated with piston-cylinder units having pistons adapted tobe supplied at one end with a pressure medium for moving the couplingmembers to a different operating position and being spring-loaded at theother end for moving the coupling members back.

2. Description of the Prior Art

In drilling technology it may be necessary for a pipe or "casing" to beentrained downwards by a drill column, which usually comprises a numberof parts and ends at the bottom in a drilling head or the like, withoutit being necessary or possible to use a special pipe-holder or releasingdevice. This happens inter alia when the drill column is relatively longand a casing, tubular shell, borehole lining or the like is needed onlyat the bottom of the drill column, i.e. mainly in boreholes under waterin the offshore area, e.g. in the case of bored pipes and the like.

A unit comprising coupling members in the form of radially movable boltscan be incorporated in the drill column at the place which is intendedto be near the top end of the entrained pipe or casing. The couplingmembers engage in holes in the pipe and can be held in position byhydraulic pressure. During drilling, they transmit rotation and axialmotion from the drill column to the pipe. When the pipe has reached thedesired depth during drilling, e.g. when it has reached hard groundafter boring through an unstable area, the pipe has to be detached fromthe column. To this end, the retaining pressure on the bolts is relievedby a cable extending along the drill column from above ground, so thatthe bolts move radially inwards under spring pressure and come out ofthe openings in the pipe. The column can then be used for furtherdrilling, whereas the pipe remains in position. A connection of thiskind between a drill column and a pipe must be made above ground, sinceotherwise the bolts cannot go into the openings in the pipe. Also, it isimpossible to couple the drill column to the pipe subsequently, as isdesirable in certain cases.

BRIEF SUMMARY OF THE INVENTION

The object of the invention is to produce a device for coupling a drillcolumn to a pipe or the like, which enables the column to be repeatedlyconnected to a pipe, casing or the like and the connection to be madeeven without direct access to the place of connection, more particularlyunder water. The invention also aims at a particularly advantageousconstruction, for practical requirements, of a device for releasablyconnecting a drill column to a pipe or the like. Other associatedproblems covered by the invention will be clear from the followingdescription of the disclosed solution.

The invention is characterized by an actuating system for thepiston-cylinder units supplied by a single pressure-medium line from apressure-medium source above ground, the actuating system comprising adirectional control valve switchable by a pressure-medium actuator andhaving at least three connections, of which a first is connected to apressure-medium supply line, a second is connected to at least some ofthe cylinder-piston units and a third is connected to an outlet line,the pressure-medium actuator being connected to the supply line and acoupling, ratchet or the like active in one direction is providedbetween the actuator and the adjustable part of the directional controlvalve.

The device can be used for coupling the drill column, releasing thecoupling and making a new connection when desired. This is done insimple manner by building up or releasing the pressure in a singlepressure-medium line.

Advantageously the actuator is a piston-cylinder unit with a returnspring which can be incorporated in the unit or associated with aconnected part.

A pressurizing valve is advantageously disposed in the line leading tothe first connection of the directional control valve, thus ensuring aparticularly advantageous time sequence of operations in the system.

In another embodiment of the device, an openable non-return valve isprovided in the line leading from the second connection of thedirectional control valve to the piston-cylinder units and the controlline of the non-return valve is connected to a fourth connection of thedirectional control valve. This ensures particularly reliable operationof the device.

The pressure-medium line leading to the actuating system can have anysuitable shape, and can also be a line leading along the column. It isparticularly advantageous for the pressure-medium line to be a centralcavity in the drill column, i.e. through the interior of the componentpipes. Depending on the functions to be performed by the drill column inassociation with a tool or other unit, it may be advantageous to providea seat in a central cavity of the device for a sealing piston lowerableinto the drilling column by a cable. After the device has been used in acoupling or uncoupling process, the piston is pulled out again, leavinga continuous open passage in the drill column for other purposes, moreparticulary for flush cleaning.

There are various possible methods of constructing the coupling members.An advantageous embodiment is characterized by coupling members eachmovable against the force of a spring relative to the pistons of thepiston-cylinder units, the coupling members each having a slope at itsfront end. The device, when incorporated in a drill column, can then belowered over the end of a pipe, whereupon the coupling members arepressed back irrespective of the position of the piston in contact withthe edge of the pipe, and thereafter remain against the pipe inner walluntil they can take up the desired position, i.e. enter openings in thepipe or the like to be coupled or extend under or over a surface on thepipe.

Irrespective of the rest of the construction, the coupling members canbe bolts, bars or the like or alternatively can be toggle levers. Thecylinder-piston units for actuating the levers may more particularly bedisposed parallel to the longitudinal axis of the device.

The coupling members can be disposed and constructed so as to transmit adownward and/or upward force from the drill column to the pipe.Depending on requirements, therefore, only coupling members transmittingforce in one direction may be provided. Alternatively, there may be twogroups of coupling members, one transmitting force downwards and theother transmitting force upwards.

More particularly the coupling members can be in the form of bearingmembers having a bearing surface adapted to be brought against a surfaceon the pipe or the like. All the coupling members may be bearing membersof the aforementioned kind, e.g. if only an axial force, not a torque,has to be transmitted from the drill column to the pipe.

In an alternative construction, depending on requirements, the couplingmembers are a number of bearing members and bars spaced apart in theaxial direction of the device. The only purpose then served by thebearing members will be to bring the bars level with the openings in thepipe when the drill column is lowered relative to the pipe. The bearingmembers will then act as abutments. Alternatively they can exertpressure on the pipe from below. More particularly the bars can transmitmainly torque and the bearing members can transmit mainly axial forcefrom the drill column to the pipe.

In another embodiment, the top edge of the pipe to be coupled hasrecesses for bringing into engagement with coupling members. Thisprovides an advantageous connection since the coupling members caneasily enter the recesses, and also enables torque to be transmittedwhen required.

If the pipe to be coupled must not be rotated but only axially entrainedby a drill column which rotates during operation, advantageously, aninternal member connectable to parts of the drill column is rotatablymounted in a housing containing the coupling members.

BRIEF DESCRIPTION OF THE DRAWINGS

Other details, features and advantages of the invention will be clearfrom the following detailed description of embodiments with reference tothe accompanying drawings wherein:

FIG. 1 is an elevational and part cross-sectional view of part of aplatform with drilling equipment and a drill column showing one possibleapplication of the device of the invention;

FIG. 2 is a longitudinal cross-sectional view of another embodiment of adrill column and a pipe to be coupled in accordance with the invention;

FIG. 3 is a cross-sectional and partly diagrammatic view of anembodiment of the device in detail;

FIG. 4 is a diagram of a valve;

FIG. 5 is a view similar to FIG. 2 of a modified embodiment of thedevice;

FIG. 6 is an enlarged cross-sectional view of another embodiment of acoupling member;

FIG. 7 is a view similar to FIG. 5 showing another embodiment of thedevice in longitudinal section;

FIG. 8 is an enlarged detail view of another embodiment of the devicewith a tube in top view; and

FIG. 9 is a cross-sectional view taken along line IX--IX in FIG. 8.

DETAILED DESCRIPTION

FIG. 1 shows part of a platform 1, e.g. in offshore use, containingdrilling equipment 2 suitable for the air-lift drilling process andcomprising a power-driven rotary head 3. Reference 4 denotes a drillcolumn made up of a number of tubular parts 4a and reference 5 denotes apipe or casing temporarily entrained by the column. The column containsa device 6 for coupling column 4 to pipe 5. The column parts 4a arereleasably connected to one another and to device 6 by flanges 13.

In the embodiment in FIG. 1, the drill-column part 4' comprises a knowntelescopic device 7, a drill stem 8 and a drilling tool 9 in the form ofa drilling head having undercutters, eccentric tools 9a or the likewhich are radially extendable over the diameter of the drilling head.

FIG. 2 shows another embodiment of a drill-column part 4" underneath andadjacent the device 6 and comprising a number of stabilizers 10 or thelike and a drilling head 11 without an eccentric bit. As in other partsof the description, reference 5 here denotes a pipe or casing to beentrained.

FIG. 3 shows an embodiment of a device comprising a casing 14 containingan inner pipe 15 with a free internal passage 16. Pipe 15 is acontinuation of the individual tubular parts 4a (FIG. 1) of the drillcolumn 4. Casing 14 contains piston-cylinder units 17, 18 in twodifferent planes or levels E1 and E2. Units 17, 18 are distributedaround the periphery at equal angular intervals. There can be e.g. fouror more units. Each unit 17 contains a cylinder 19 and a piston 20. Thecylinder chamber 21 can be supplied with pressure medium via adiagrammatically-indicated line 22. Piston 20 is loaded by a compressionspring 23 which resiliently urges it radially inwards. Reference 24denotes a coupling member in the form of a bar having a shank 25 and athickened end part 26 extending into an evacuated cavity 27 in piston20. A compression spring 28 is disposed between piston 20 and a shoulderon bar 24 and resiliently pushes the bar away from piston 20. Bar 24 canbe pushed against the force of spring 28 radially relative to piston 20,i.e. into the piston. The front end of bar 24 has a bevelled or slopingend face 24a.

Unit 18 likewise comprises a cylinder 29 containing a movable piston 30permanently connected to a bearing member 34. The cylinder chamber 31can be supplied with pressure medium via a line 32 parallel to line 22.Piston 30 is loaded by a compression spring 33 which resiliently pushesit radially inwards. References 35 and 36 denote guide bolts engagingrespectively in grooves in bars 24 or members 34 and likewise preventingparts 24 and 34 from rotating around their longitudinal axes. The frontend of each bearing member 34 has a bottom bearing surface 37 which canabut the top end face 38 of pipe 5.

Pipe 5 is formed with radial openings 39, the number and spacing betweenthe openings being such that bars 24 can enter them.

Reference 40 denotes an actuating system for the piston-cylinder units17 and 18. A non-return valve 41 is provided in an opening in the wallof pipe 15 so that pressure medium, more particularly water, suppliedthrough the interior 16 of pipe 15 can flow into a closed chamber 42 andthence through a connection 43 into a supply line 45 containing a filter44. Line 45 branches as diagrammatically shown, one branch 45a leadingto a pressure-medium actuator 46 constructed as a piston-cylinder unit,the side of the piston remote from the pressure-medium chamber beingloaded by a return spring 46a. Drive 46 is used for switching theadjustable part 48a of a directional control valve 48 via a coupling oradditional switching device 47 active in only one direction andconstructed e.g. on the ratchet principle. The valve, shown onlydiagrammatically in FIGS. 3 and 4, is advantageously a 4/2-way valvehaving four connections 51, 52, 53 and 54, connection 51 being connectedto a branch 45b of supply line 45 and connection 53 being connected toan outlet line 49 which can open e.g. into the annular space betweendevice 6 or column 4 and pipe 5. Connection 52 is connected to a line 50containing an openable non-return valve 55 whose control line 56 isconnected to the fourth connection 54 of valve 48. Behind valve 55, line50 branches into two portions 22, 32 leading to units 17, 18,respectively.

A sealing seat 57 in the inner pipe 15 of device 6 is provided for asealing piston 58, the bottom end of which has a sealing surface 59fitting the seat 57. At the top end of the piston there is a couplingcone 60 for a known gripping device, so that piston 58 can be loweredthrough the drill column by a cable from above ground and can also bepulled out of the column. In the drawings, reference 61 diagrammaticallyindicates a pressure-medium source, more particularly a pump, andreference 62 denotes a line portion formed by the free internal space inthe parts 4a of the drill column. By means of piston 58, the lineportion in the drill column can be used to operate device 6, whereas atother times it is available or can be used for other purposes, e.g. forflush cleaning or for the air-lift drilling process.

When piston 58 has been lowered into the drill column and device 6 isabove the end of a pipe 5 to be coupled to the column, the above-groundpump 61 can be switched on so that pressure medium, more particularlywater, is conveyed downwards through the drill column, the rest of whichis closed, and flows from the inner chamber 16 through valve 41, chamber42, connection 43 and filter 44 into line 45 and continuation 45athereof.

When the pressure in the line portion has risen to a preset amount, e.g.10 bars, actuator 46 is brought into operation, its piston reaching thelimit position at e.g. 15 bars. As a result, valve 48 is actuated byratchet 47 so as to connect connections 51, 52 and 53, 54 as shown bycontinuous lines in FIGS. 3 and 4. The pressure in the column andconnected line portions continues to rise and, at a set value of e.g. 20bars, opens a pressurizing valve 63 disposed in the other branch 45b ofsupply line 45. The supplied pressure medium can then flow via valve 48,line 50, non-return valve 55 and branch lines 22, 32 to thepiston-cylinder units 17 and 18, thus pushing out their pistons 20, 30and consequently pushing out bars 24 and bearing members 34. Pump 61 isthen switched off. The resulting pressure drop closes the non-returnvalve 55, and the piston of actuator 46 is returned to its startingposition by the force of spring 46a.

The previously-mentioned gripping device can then be lowered in thedrilling column by the cable. As soon as the gripping device strikes thecoupling cone 60 of the sealing piston 58, the coupling engages andpiston 58 can be pulled out of the column.

The drill column 4 and device 6 are then lowered. In the process, thesloping surfaces 24a of bars 24 touch the inner edge of the top end face38 of pipe 5 and are pressed inwards by the required amount against theforce of springs 28. When further lowered, they slide along the innersurface of pipe 5. The process is complete when the surfaces 37 of thebearing members 34 rest on end face 38. Even if openings 39 in the toppart of pipe 5 are not already aligned with bars 24, the bars 24nevertheless engage the openings when the drill column is subsequentlyrotated. Springs 28 then drive bars 24 into the openings, so that bothtensile and torsional forces can be transmitted from column 4 to pipe 5.The bearing members 34 ensure that bars 24 are at the right level foropenings 39 when lowered. Members 34 can also exert downward pressure onpipe 5.

If the device is to be uncoupled from pipe 5, the sealing piston 58 isfirst lowered by a cable into column 4. As soon as it rests at thesealing position, the gripping device opens and can then be pulled up.In accordance with the previously-described operation, pump 61 thenintroduces pressure medium, thus operating the actuator 46 and movingthe directional control valve 48. The pressure medium can thus flow viathe pressurizing valve 63 to the directional-control valve connection 54and into the control line 56, thus opening the non-return valve 55. As aresult of the pressure drop after switching off the pump 61, the pistonof actuator 46 is returned to its starting position by spring 46a. Line50 is now connected to the outlet line 49, so that the pressure mediumcan flow out of the cylinder chambers 21, 31 of units 17, 18 and springs23, 33 move pistons 20, 30 radially inwards into the inoperativeposition, so that bars 24 and bearing members 34 are both withdrawn frompipe 5. Device 6 is thus disconnected from pipe 5. By means of the cableand the gripping device, piston 58 can be withdrawn from column 4 sothat the column is free and available for another drilling operationindependently of pipe 5.

At any time, the drill column can be reconnected to pipe 5 by device 6,so as to carry out the individual processes in the manner alreadydescribed.

FIG. 3 shows an embodiment of device 6 for incorporation in a "flangecolumn", i.e. a drilling column with parts comprising external lines 64(FIG. 3) e.g. for conveying air. By contrast, FIG. 5 shows a device forincorporation in a "double-wall" column and, like the column parts,comprising an inner pipe 65 surrounded by an outer pipe 66, to which thecasing of the device is secured. In other respects the construction issimilar to the embodiment in FIG. 3. Similar or corresponding parts inFIG. 5 are given the same reference numbers as in FIG. 3. The actuatingsystem is shown in simplified form in FIG. 5.

FIG. 6 shows another embodiment of a coupling member, which in thepresent case is a toggle lever 71 pivotable around a stationary shaft 72in casing 74. The internal end of lever 71 is connected by a link pin 73to the piston rod 75 of a piston-cylinder unit 77, the cylinder beingpivoted by means of a spigot 76 on casing 74. The piston rod 75 and itsprolongation are substantially comparable with bar 24 and shank 25 ofunit 17 in FIG. 3, so that the remarks there apply here correspondingly.

The coupling member 71 can be a bar for engaging an opening in a pipe,or can be a bearing member. The latter is shown in FIG. 6. The togglelever 71 has a bearing surface 67 which can abut a co-operating surface69 at the underside of an inwardly projecting collar 78 on the pipe.This part of lever 71 also has a slope 70, so that when the device islowered it can slide over the edge of collar 78 and give way inwardly.Reference 79 denotes an abutment for a surface on the other arm of lever71, thus providing support.

Casing 74 has a co-operating surface 80 facing the end face 68 at thetop end of pipe 5 and used for bearing the casing when pipe 5 is to beloaded in the downwards direction. Alternatively, an upward axial forcecan be exerted on pipe 5 by member 71 in the position shown in FIG. 6.

FIG. 7 shows an embodiment of a device 86 for use when the drill columnis to exert only an axial force on pipe 5 in one or the other direction,without transmitting a torque. In the last-mentioned embodiment, the toppart of a casing 84 contains coupling members 81 sloping at the frontend and an associated actuating system 40 as desoribed hereinbefore inconjunction with Figs. 3 and 4. The casing also has a co-operatingsurface 80 facing the end face 68 of pipe 5, as shown in FIG. 6 anddescribed in connection therewith.

The casing has a projection 85 screwed to it at the bottom, on which anannular part 87 is rotatably mounted on rolling bearings 82, 83 andpermanently connected to a tubular inner part 88 of the device. Part 88forms the continuation of the drilling-column parts 4a and is connectedto them by flanges 13. The inner part can thus rotate with the entiredrill column relative to casing 84, i.e. relative to pipe 5.

Pressure medium is supplied to the actuating system 40 via thenon-return valve 41 through a number of openings 89 in the inner part 88and an annular channel in the cylindrical wall 90 of casing 84surrounding the inner part.

As shown in FIG. 5, the sealing piston 58 advantageously has an innerpassage 94 with one or more top inlet openings 95, a downward outletopening 96 under the sealing surface 59, and a valve 97. The shank 99 ofvalve member 98 is connected to the coupling cone 60, which is axiallymovable over a certain distance, limited by an abutment. In theinoperative state, both parts are pressed downwards by a spring (notshown), thus closing valve 97. When, at the end of a process forcoupling or uncoupling the drill column, piston 58 and pipe 5 have to beraised and the gripping device on the lowered cable has gripped thecoupling cone 60, the tension in the cable at the beginning of theupwards motion initially moves the coupling cone 60 upwards togetherwith valve member 98, so that the valve 97 is opened. Consequently, theamount of liquid, i.e. water, in the drill column above piston 58 canflow downwards through passage 94 and opening 96. A similar passage andvalve can be present in all other embodiments of the device.

FIGS. 8 and 9 illustrate an embodiment in which the top edge region ofthe pipe 5' or coupling has a number of recesses 92, e.g. four,regularly distributed around the periphery. Coupling members 91 canengage in the recesses 92 and thus transmit a downward force and/ortorque from the drill column to pipe 5'. In other repects the embodimentcan be constructed as required. It can have other of thepreviously-described features, so that the previous remarks applycorrespondingly here.

The invention can be operated in various ways, so that good account canbe taken of numerous cases as required. It can be used for entraining apipe in the axial direction and simultaneously rotating it; moreparticularly the bottom end of the pipe, which can bear a cutting rim orthe like, will be approximately level with the drilling head at thebottom end of the column. In other cases the pipe can be entrainedaxially without rotation, e.g. when the pipe has to be lowered.Operation can then be as shown in FIG. 1. Pipe 5 is guided so that thedrilling head 9 on the column goes beyond the bottom end of the pipe.The eccentric bit 9a is extended and a cavity is bored in the diameterof the pipe. At the end of a boring operation the eccentric bit 9a isretracted and the drilling head 9 is lowered to the bottom of theborehole, thus relieving the load. Pipe 5 can then be lowered incontrolled manner by lowering the top part of the drill column by meansof device 6, thus retracting the telescopic device 7. When pipe 5 hasreached its end position, device 6 can be actuated for uncoupling pipe 5from the drill column 4.

All features mentioned in the preceding description or shown in thedrawings, insofar as permitted by the prior art, should be regarded ascoming under the invention, either alone or in combinations.

I claim:
 1. A device for incorporation in a drill column for releasablyconnecting the drill column to a pipe or similar hollow membercomprising:coupling members for attaching to the pipe; piston-cylinderunits operatively associated with said coupling members and havingpistons adapted to be supplied at one end with a pressure medium formoving said pistons and coupling members to a coupling position andspring-loaded at the other end for resiliently urging said couplingmembers toward a non-coupling position; and an actuating system foroperating said piston-cylinder units comprising,a pressure-medium sourceaboveground, a single pressure-medium line connected to saidpressure-medium source, a directional control valve having an adjustablepart and at least three connections, a pressure-medium supply lineconnected to said single pressure-medium line and a first correction ofsaid connections, at least some of said cylinder-piston units beingconnected to a second connection of said connections, an outlet lineconnected to a third connection of said connections, a pressure-mediumactuator connected to said pessure-medium supply line to be operatedthereby, and a coupling means active in one direction operativelyconnected between said actuator and said adjustable part of saiddirectional control valve.
 2. A device as claimed in claim 1wherein:said actuator comprises a piston-cylinder unit with a pistonreturn spring.
 3. A device as claimed in claim 1 and furthercomprising:a pressurizing valve in said pressure-medium supply lineleading to said first connection of said directional control valve.
 4. Adevice as claimed in claim 1 and further comprising:a connecting lineleading from said second connection of said directional control valve tosaid piston-cylinder units; a non-return valve in said connecting lineopenable in the direction of said piston-cylinder units, a fourthconnection on said directional control valve; and a control lineconnected between said non-return valve and said fourth connection.
 5. Adevice as claimed in claim 1 wherein:said pressure-medium line connectedto said pressure-medium source comprises a central cavity in the drillcolumn.
 6. A device as claimed in claim 1 and further comprising:acentral cavity in the device; and a non-return valve operativelyconnected between said actuating system and said central cavity.
 7. Adevice as claimed in claim 1 and further comprising:a central cavity inthe device; a sealing piston lowerable by a cable into the drill column;and a seat in said central cavity engageable with said sealing piston.8. A device as claimed in claim 7 and further comprising:a passage insaid sealing piston; and a value in said passage adapted to be actuatedby a force transmitted by the cable.
 9. A device as claimed in claim 1wherein:said coupling members comprise members for transmitting adownwardly directed force from the drill column to the pipe.
 10. Adevice as claimed in claim 1 wherein:said coupling members comprisemembers for transmitting an upwardly directed force from the drillcolumn to the pipe.
 11. A device as claimed in claim 1 wherein:some ofsaid coupling members are operatively associated withcoupling-member-receiving holes in the pipe to be coupled.
 12. A deviceas claimed in claim 1 and further comprising:spring means between saidcoupling members and respective pistons for resiliently urging saidcoupling members relatively to said respective pistons of saidpiston-cylinder units, said coupling members being movable relative tosaid pistons; a pipe-engaging outer end on each coupling member; and asloping surface at said outer end.
 13. A device as claimed in claim 1wherein:said coupling members comprise radial bars.
 14. A device asclaimed in claim 1 wherein:said coupling members comprise toggle levers.15. A device as claimed in claim 1 wherein:said coupling memberscomprise bearing members each having a bearing surface adapted to beengageable against a surface on the pipe.
 16. A device as claimed inclaim 1 wherein:said coupling members comprise movable bearing members;and further comprising a housing having at least one stationary surfacefacing a surface on the pipe.
 17. A device as claimed in claim 1wherein:said coupling members comprise a plurality of bearing membersand bars spaced apart in the axial direction of the device.
 18. A deviceas claimed in claim 1 wherein:recesses are provided in said top edge ofthe pipe; and said coupling members engage in said recesses for couplingwith the pipe.
 19. A device as claimed in claim 1 and furthercomprising:a housing containing said coupling members; and an internalmember rotatably mounted in said housing and connectable to parts of thedrill column.